Capacity is always an issue with respect to the transmission of data packets, such as an Internet Protocol (IP) data packet, over a data network, such as an IP network, particularly when low-speed links, such as T1/E1 lines, are involved. In order to improve capacity, methods have been proposed for multiplexing IP/cUDP/PPP packets and IP/UDP/RTP packets over a link that utilizes a point-to-point protocol (PPP). One proposed method generally involves a node in an IP network receiving multiple IP/cUDP/PPP packets, or multiple IP/UDP/RTP packets. The node generates a Frame Relay frame by multiplexing the multiple packets and wrapping the multiplexed packets with a new transport-layer header, such as a multi-protocol label switching (MPLS) header, that is based on the addresses included in the headers of the received data packets. The multiple packets and new transport-layer header are then combined into a single frame and transmitted to a destination node identified by the new transport-layer header. When the frame is received at the destination node, each of the multiple packets are extracted from the frame and routed to their intended destination based on the IP/cUDP/PPP, or IP/UDP/RTP, header included in the packet.
MPLS provides a link layer independent transport framework for the transmission of IP data packets. Since MPLS is link layer independent, it can run over any one of multiple packet mode links, such as ATM, Frame Relay, Ethernet, and PPP. However, since the format of the addresses in each header depends upon the protocol used by the link layer, the new transport layer heading methods cannot be used to multiplex packets of different protocols over a link. In addition, since the proposed method just multiplexes the multiple data packets and wraps a new header around them, the method fails to take advantage of other capacity saving opportunities presented by the multiplexing of multiple data packets.
Therefore, a need exists for a method for multiplexing packets of different protocols over a link and for achieving additional capacity savings.